Double-ended high frequency electron tube



Nov. 2, 1965 w. J. HELWIG 3,215,886

DOUBLE-ENDED HIGH FREQUENCY ELECTRON TUBE Filed Dec. 6, 1961 2 Sheets-Sheet l Nov. 2, 1965 w. J. HELWIG 3,215,886

DOUBLE-ENDED HIGH FREQUENCY ELECTRON TUBE Filed Dec. 6, 1961 2 Sheets-Sheet 2 United States Patent 3,215,886 DOUBLE-ENDED HIGH FREQUENCY ELECTRON TUBE William J. Helwig, Kearny, N.J., assignor to Radio Corporation of America, a corporation of Delaware- Filed Dec. 6, 1961, Ser. No. 157,382 Claims. (Cl. 313313) This invention relates to electron discharge tubes, and particularly to electron tubes of the double-ended type, and to a method of fabricating such tubes.

In certain electron tube applications, such as in the amplification of high frequency electronic signals, it is the practice to use types of electron tubes known as double-ended tubes. These tubes are characterized in that the various electrodes of the tubes are electrically connected with and supported from different portions of the tube envelope, each envelope portion serving as a terminal for its associated electrode. One type of doubleended tube, for example, is a grounded-grid triode wherein the anode is brought out through the top end of the tube, the grid is connected with a side portion of the tube, and the cathode and heater are electrically connected through the bottom end of the tube. The different envelope portions are insulated from one another, and socketing means are provided for making electrical connection to each of the envelope portions.

One advantage of this type of construction is that the capacitive coupling between the tube electrodes is very small. That is, in comparison with single-ended tubes wherein all the electrode connections are brought out through one end of the tube, much larger spacings are provided in the double-ended tubes between the different electrode supporting members. The result of this larger spacing is that the inter-electrode capacitance of doubleended tubes is much lower than that of single-ended tubes. Also, the double-ended tube permits use of large area electrode supporting members and conductive terminals having small inductance whereby the total inductance of the electrodes is also much smaller than that of single-ended tubes. Low inter-electrode capacitance and electrode inductances are desirable for efficient performance of electron tubes in high frequency applications, as known, and account for the preference of double-ended tubes over single-ended tubes for many of these applications.

A problem associated with double-ended tubes, however, is that since the various tube electrodes are supported from different parts of the tube envelope, the accuracy of the spacing and positioning of the electrodes within the tubes is dependent upon the dimensional accuracy of the tube envelopes. Thus, in order to provide close control over the spacing and alignment of the tube electrodes, which, as known, are especially critical in tubes used in high frequency applications, it is necessary to fabricate and assemble the envelope parts and the electrode supports to very close tolerances. For this reason, tubes of this type are generally more expensive than single-ended tube types wherein the spacing and alignment of the electrodes are generally independent of the dimensional variations in the tube envelopes.

A further reason for the large cost of double-ended tubes is that fabrication of the tubes usually involves assembling separate sub-assemblies consisting of the individual tube electrodes and the envelope portions to which the electrodes are secured, and then assembling all the sub-assemblies into a complete tube. Such practice requires a number of separate assembling operations which are expensive because of the labor involved. Such practice also requires the use of numerous accurately dimensioned and expensive assembly jigs. Moreover,

since the multiple tolerances of all the sub-assemblies may 3,215,886 Patented Nov. 2, 1965 combine to produce large dimensional variations upon assembly of the tube, great skill and care must be exer cised in the assembly of the tube to provide the necessary close tolerance electrode spacings. For this reason, prior art tubes of the double-ended type do not lend themselves to automatic mechanical fabricating means.

A still further problem associated with the prior art high frequency, double-ended tubes is that the expense and difficulty of assembling the tubes is increased as the size of the tubes is decreased. The tube parts, assembly fixtures, and jigs become smaller and progressively more difficult to handle and manipulate as the tube size is decreased. Moreover, because certain jigging elements extend into the tube to accurately position the tube electrodes, the reduction in size of the electron tube is limited by the space required by the jigging elements.

Therefore, an object of this invention is to provide an improved electron tube structure and method of assembly wherein the problems, expenses, and limitations encountered in the prior art are largely avoided or reduced.

Other objects of this invention are to provide an improved tube and method of assembly wherein simple and inexpensive jigging fixtures may be employed for providing the desired electrode spacings largely independently of the envelope portions and electrode supports; wherein the tube parts lend themselves to assembly by automatic mechanical means and by relatively unskilled tube assemblers; and wherein, without corresponding increases in cost, the size of the tube may be reduced to sizes previously considered impractical.

For achieving these objects in accordance with this invention, an electron tube and method of assembly are provided wherein a number of sub-assemblies may be first pre-assembled and then assembled along with other tube parts in an assembly and brazing jig. Each subassembly comprises a small number of parts, usually but two, which are adapted for easy assembly in a jig of simple design. Thereafter the sub-assemblies: and other tube parts are loaded into an assembly jig, jigging elements therein guiding the parts into properly spaced relationship. The jigging elements provide close control of the spacings between the electrodes and between certain ones of the other tube parts, While certain ones of the subassemblies and tube parts provide guide and stop means for controlling the positioning of still other tube parts. The assembled tube electrodes, electrode supports, and envelope portions are then brazed together to form a unitary assembly. The brazed assembly is removed from the jig and the remaining tube parts are added thereto, seating means being provided in the assembly for receiving and guiding the remaining parts in proper relation therewith. The tube is then exhausted and sealed.

As will be described in detail hereafter, among the advantages of the tube construction and method of assembly according to this invention are that the various tube parts making up the sub-assemblies and the complete tube are largely self-aligning whereby postioning and proper spacing of the tube parts may be readily achieved using simple fixtures and relatively untrained assemblers. Further, the self-aligning features of the tube parts and sub-assemblies simplifies the final assembly jig and reduces the number of jigging elements required. The effect of this is that less space Within the tube is taken up by jigging elements, thereby permitting greater reductions in the size of the tubes than was practical in the prior art.

A further feature of this invention is the provision of novel means for socketing the electron tube wherein by simple modification of the tube structure the tube may be socketed in a number of different ways depending upon the particular application in which the tube is to be used.

Still further features and advantages of the present invention will become apparent as the description thereof proceeds in connection with the attached drawings wherein:

FIG. 1 is a longitudinal section of an electron tube made according to this invention;

FIGS. 2, 3 and 4 are perspective views of tubes made according to this invention showing different electrode terminal and socketing configurations;

FIG. 5 is a longitudinal section of a jig which may be used for assembling one of the sub-assemblies of the tube shown in FIG. 1; and,

FIG. 6 is a longitudinal section of a brazing jig which may be used for assembling and brazing together certain parts of the tube shown in FIG. 1.

The tube As shown in FIG. 1, the electron tube 18 may be used as a grounded grid triode and comprises an envelope 12 including an annular ceramic sleeve member 14 having end surfaces 13 and 15 lying in spaced parallel planes normal to the longitudinal axis of the envelope. These end surfaces may be metallized for braze sealing. The bottom portion of the envelope includes a conducting tubular member 16 of metal having an upper end 17 sealed to the lower end surface 15 of the annular ceramic member 14, preferably by braze sealing and extending away therefrom. Closing the other, lower end 18 of tubular member 16 is a ceramic header member 20 also brazed sealed to member 16. The ceramic header member 20 is provided with a plurality of bores 21 through which a plurality of electrode support and lead-in conductors 22 and 23 extend in vacuum-tight relation.

The other end of envelope 12 includes a conductive anode support enclosure 26 comprising an anode eyelet 27 and an inverted cup-shaped anode cap 28. The anode eyelet has two different diameter tubular sections 30 and 31 joined by a radially extending flange 32. The smaller diameter tubular section 30 engages and supports an anode electrode 38. The end 34 of the larger diameter, tubular section 31 is braze sealed to the annular ceramic member 14. Flange 32 serves as a seat for anode cap 28 which is sealed thereto.

The electrodes within envelope 12 includes the anode 38, a grid 40, and a cathode 42, said electrode being in coaxial, telescoped relation. Anode 38 and grid 49 are open-ended tubular structures. Cathode 42 comprises an open-ended tubular support sleeve 44 capped by a cathode cup 45 having an electron emissive material coated on the outer cylindrical surface thereof. Anode 38 is electrically connected to and secured to anode eyelet 27, as described. Grid 40 is electrically connected to and supported by a grid support member 48 having a centrally disposed well or tubular portion 49 in which the end of grid 40 is snugly received. A longitudinally extending peripheral tubular portion 50 of support member 48 engages and is secured to the inside Wall of tubular member 16. End 51 of tubular member 50 engages a face of wafer 20 for providing the correct spacing of the wafer from the tube electrodes, as will be described. The cathode sleeve 44 is mounted on a radially extending dish-like flange 55 having a centrally disposed tubular portion 57 for receiving the end of cathode sleeve 44. An inwardly directed annular lip 58 may be provided at the end of tubular portion 57 for providing flange 55 with a stop means for the end of sleeve 44. Flange 55 is supported on three conductors 22 spaced 120 apart around a circle, the plane of which is perpendicular to the longitudinal axis of the tube, the conductors 22 extending into three bores 21 through the ceramic wafer 20. A heater 62 is contained within the cathode sleeve 44, the ends of the heater extending outwardly therefrom and being secured to and supported on the ends of two conductors 23 also extending into bores 21 through the ceramic wafer. As will be described hereinafter, all the joints between 4 the envelope parts referred to are made by brazing, copper being the principal brazing material used in one embodiment.

Tube 10, shown in FIG. 1, may be used as a grounded grid triode. In such application the control grid acts as a capacity shield between the anode and the cathode of the tube. The grid support 48 and tubular member 16 connected thereto serve as effective shielding means for shielding the lower end of cathode sleeve 44 and flange 55 from the anode enclosure 26 and anode 38.

Inductance of the electrodes of tube 10 is also maintained at low values. As known, electrode inductance is dependent upon the area of the electrode terminals, the larger the terminal area the smaller the electrode inductance. In tube 10, anode cap 28 provides a large area terminal for anode 38. The area of the grid and cathode terminals depends upon the manner in which the tube is to be socketed and the particular tube construction or modification used. That is, the tube may be readily modified to adapt it to different types of socketing arrangements depending upon the intended application of the tube. This feature is important to tube manufacturers since it permits the fabrication of several different tube types using essentially the same fabricating facilities.

As mentioned, three conductors 22 extend through the header wafer 20 and engage and support cathode flange 55. In one socketing arrangement for tube 10 (FIGS. 1 and 2), two of the conductors 22 are cut off close to the outer face of wafer 20, only the third conductor extending longitudinally therefrom. For socketing the tube, a conventional type socket is employed (not shown) having receptacles for receiving the extending cathode conductor 22 and the two heater conductors 23. A fourth conductor 65 is provided which extends parallel to conductors 22 and 23 and which is fixed to tubular member 16. Conductor 65 is also received within the socket receptacle. A separate socket clip is provided for making electrical contact with the anode cap 28. This socketing arrangement may be used for relatively low frequency applications.

For higher frequency applications wherein it is desired to reduce the total inductance associated with the grid electrode, the grid conductor 65 is not used (FIG. 3). Instead, a coaxial type clip (not shown) may be used for engaging and making electrical contact with tubular member 16, thereby eliminating the inductance of the relatively small area conductor 65. A socket is used for making electrical connection with the heater and cathode conductors 22 and 23, respectively, and a coaxial type clip for the anode cap 28.

For still higher frequency applications wherein it is also desirable to reduce the total inductance of the cathode electrode 4-2, all three cathode conductors 22 are extended longitudinally outwardly from the face of wafer 20 and a conductive cylinder 68 is secured thereabout (FIG. 4) and in engagement wit-h wafer 20. Separate coaxial type clips are used for engaging cylinder 68, tubular member 16, and anode cap 28, and a small socket is used for engaging the heater conductors 23.

As mentioned, sub-assemblies of certain ones of the tube parts may be pre-assembled prior to final assembly of the tube. One sub-assembly 70 (FIG. 5) consists of the anode 38 and the anode eyelet 27, and another subassembly 72 (FIG. 6) consists of the grid support 48 and the tubular member 16. For assembling the anode subassembly 70, the anode eyelet 27 is dropped into a jig 75, as shown in FIG. 5. A quill 76 is inserted in anode 38 and the quill carrying anode 38 is guided into jig 75, the anode being press fitted (as shown in phantom) within tubular portion 30 of anode eyelet 27 and in proper coaxial relation therewith. The grid sub-assembly 72 is assembled in similar fashion, the tubular member 16 first being dropped into a jig similar to that shown in FIG. 5,

and the grid support 48 being press fitted within tubular member 16 by means of a quill.

As will be apparent to those skilled in the art, the jigging fixtures for assembling sub-assemblies 70 and 72 are of very simple design and construction. Moreover, the simple tubular shapes of the sub-assembly parts lend themselves to easy assembly whereby automatic assembly means and unskilled assemblers may be employed to assemble these parts. Further, as will be described, the tube electrode spacings are not dependent upon the match or fit between the sub-assembly parts, hence the dimensions of the mating surfaces of these parts need not be held within tight tolerances. The degree of tightness of fit between the sub-assembly parts is also not critical since the parts are brazed together during the tube brazing operation.

For assembling the sub-assemblies and other tube parts into a tube assembly, a jig 80 as shown in FIG. 6 is used. The jig 80 comprises an outer generally cylindrical hollow housing 82 having a wall portion 84 adapted to re ceive in relatively loose slideable fit therein the ceramic sleeve 14. A jigging assembly 88 is centrally disposed within the jig and comprises a central post 90, an inner jigging cylinder 91, an inner spacer cylinder 92, an outer jigging cylinder 93, and an outer spacer cylinder 94. The inner and outer jigging cylinders 91 and 93 extend upwardly a predetermined distance beyond the upper ends of the central post 90 and the spacer cylinders 92 and 94 to partially expose the surfaces of the jigging cylinders for the purpose of receiving tube parts thereon.

As shown in FIG. 6 the jigging assembly 88 is adapted to receive the cathode support sleeve 44, the grid 40, and the anode 38 in a desired spaced relationship. The inner jigging cylinder 91 is of such internal diameter that the cathode support sleeve 44 is snugly received therein. The outer diameters of the inner jigging cylinder 91 and the outer jigging cylinder 93 are such that the grid 40 and the anode 38 are snugly received around the cylinders 91 and 93, respectively. The wall thickness of the inner jigging cylinder 91 thus determines the spacing between the cathode support sleeve 44 and the grid 40. Likewise, the wall thickness of the outer jigging cylinder 93 and the inner spacer cylinder 92 determine the spacing between the grid 40 and the anode 38. The center post 90 and the spacer cylinders 92 and 94 are provided with stepped ends 96, 97, 98 and 99 so as to properly longitudinally locate the anode 38, grid 40, cathode sleeve 44, and the heater 62 respectively. The jig 80 may be made of a material which is essentially an alloy of nickel and iron known as Nichrome and which is surface oxidized to make it nonwettable by copper.

The method of fabrication Prior to assembly of the tube 10 within the jig 80, several of the tube parts may be provided with metallic coatings in order to facilitate brazing of the tube. Flange 55, grid support 48, and conductors 22 and 23 may be provided with brazing material in the form of a coating of copper of the order of 1 to 3 mils thick. The copper coating may be applied by any known methods, although electroplating has proven most satisfactory for providing the copper on all the surfaces of these parts. The ceramic wafer 20 is metalized about its outer periphery 24 and on the walls of bores 21 with molybdenum. A satisfactory method of providing this metalized coating is to coat the entire wafer with molybdenum by any known metalizing process and then grind off the metalized coating from the fiat surfaces of the ceramic. Also, the end surfaces of the annular ceramic portion 14 are first metalized with molybdenum and then provided with a further coating of copper 2 to 3 mils thick.

Having thus prepared certain parts of the tube, all the parts thereof excepting the anode top cap 28 and the cathode cup 45 are assembled within the jig 80.

During the assembly of the tube, the jig 80 is oriented with its open end up and the first part to be loaded therein is the anode sub-assembly 70. As shown in FIG. 6 the tubular anode 38 is received snugly around jigging cylinder 93 thereby providing exact positioning of the anode. Thereafter the annular ceramic sleeve 14 is dropped into the jig and into engagement with the end 34 of tubular portion 31 of anode eyelet 27. Ceramic sleeve 14 performs no electrode positioning or alignment functions, hence its dimensions need not be held within close tolerances. Moreover, since the relatively large thickness of the wall of the ceramic sleeve 14 ensures proper engagement of the end of tubular portion 31 with the top end surface of the ceramic sleeve, the ceramic sleeve need not be positioned in perfectly concentric relation with anode eyelet 27.

The grid 40 is then loaded into the jig, the grid being received snugly around inner jigging cylinder 91. The grid sub-assembly 72 is then added to the mount assembly, the centrally disposed tubular portion 49 thereof being disposed about and engaged with the upper end of grid 40.

Grid 40 is held firmly in position by jigging cylinder 91 and upon insertion of the grid end into tubular portion 49, the grid sub-assembly 72 is thus guided into correct concentric relation with the grid. The grid subassembly is moved axially along the grid causing the grid end to be inserted in and through tubular portion 49 until the upper end 18 of tubular member 16 engages the stop provided by the end surface 15 of ceramic sleeve 14. An advantage of this mounting arrangement is that proper radial and axial positioning of grid sub-assembly 72 within the tube 10 is provided by the other tube portions rather than by jigging elements. This is desirable because it reduces the number of jigging elements used and hence the amount of space between parts required within the tube. Also, positioning of sub-assembly 72 by the other tube portions imposes no greater dimensional accuracy requirements either on the positioning of tube portions or sub-assembly 72 since the sub-assembly does not require critical positioning. The tube electrodes are positioned by the jigging cylinders independently of sub-assern bly 72.

The cathode support sleeve 44 is then loaded into engagement with jigging cylinder 91, as shown. Flange 55 is then dropped onto the end of the cathode sleeve, lip 58 at the end of tubular portion 57 thereof providing stop and seating means for the flange 55. In some instances, flange 55 and cathode sleeve 44 are preassembled and inserted into the jig as a sub-assembly. The ceramic wafer 20 is then inserted into tubular member 16 until it engages the shoulder provided by the end 51 of the tubular portion 50 of the grid support 48. Both the radial and axial positioning of wafer 20 is provided by the tube parts rather than by the jig which further reduces the number of jigging elements required. Moreover, use of shoulder 51 as a positioning or stop means for wafer 20 avoids the use of an indentation or shoulder in tubular member 16, the support 48 serving this function as well as a shielding function. Another advantage of this is that it permits the use of a tubular member 16 having a constant cross-section, thereby permitting use of conventional and commercially available clip-type sockets for making electrical contact therewith.

Prior to the insertion of wafer 20, heater 62 has been secured to two conductors 23 extending through bores 21 of the ceramic wafer. The remaining conductors 22 are then dropped through the bores 21 of the ceramic wafer until they engage the cathode flange 55. Alternately, the conductors may be threaded through the wafer bores 21 prior to insertion of the Wafer into the jig. The length of conductors 22 and 23 used depends upon the type of socketing arrangement to be employed. For the tube shown in FIG. 2, two short conductors and one long conductor 22 are used. The long conductor 22 extends from flange 55 (FIG. 1) through wafer 20 and longitudinally away from the tube envelope 12. The short conductors 22 extend from flange 55 through wafer 20, but end substantially flush with the outer face of the wafer. Conductor 65 is then spot welded onto the end of tubular member 16 eXtending beyond wafer 20. Conductor 65 and heater conductors 23 extend the same length as the long cathode conductors 22.

For the tube shown in FIG. 3, conductor 65 is omitted.

For the tube shown in FIG. 4, three long conductors 22 of equal length are used, and the conductive cylinder 68 then disposed therearound. The three conductors hold cylinder 68 coaxially with envelope 12, one end of the cylinder resting against wafer 20. Heater conductors 23, in this case, extend further than the cathode conductors 22.

Having thus assembled the electron tube 10, less the anode top cap 28 and the cathode cup 45, the loaded brazing jig is placed in a hydrogen furnace and heated until the copper brazing material provided on the various tube parts melts. During assembly of the parts into the jig, brazing material rings 103 and 104 (FIG. 6) may also be dropped into the jig and into engagement with flange 32 of anode eyelet 27, and around tubular member 49 of the grid support 48. Also, for brazing conductors 22 and 23 to the ceramic wafer 20 and conductors 22 to flange 55, rings 105 of brazing material may be provided as shown. Upon heating, the copper brazing material provided on the various tube parts and in the brazing material rings melts and flows to form the brazed joints, including joints between the anode 38 and the anode eyelet 27 of sub-assembly 70 and between the grid support 48 and the tubular member 16 of sub-assembly 72. As mentioned, by providing brazed joints between the sub-assembly 70 and 72 joints, positive electrical and mechanical engagement of these parts with each other is assured.

Prior to exhaust and final sealing of the tube 10, the brazed tube assembly is removed from jig 80, and cathode cup 45 (FIG. 1) is inserted through the open-ended anode 38 and positioned on the top end of cathode sleeve 44. Thereafter, the anode cap 28 is dropped onto anode eyelet 27, the tube being in upright position, and flange 32 providing a seat for the anode cap. A ring of brazing material (not shown) is provided between the anode cap 28 and flange 32, or alternately, the anode cap is prior coated with a suitable brazing material. The brazing material used to seal the anode cap 28 to the anode eyelet 27 has a lower melting temperature than copper, and may comprise an alloy of nickel and gold. The reason for this is to prevent softening and loosening of the prior made copper brazes during brazing of the I anode cap.

The now completed electron tube is placed in an exhaust and heating chamber wherein the metal parts of the tube are degased, the cathode cup 45 sintered to the cathode support sleeve 44, the cathode emissive material broken down and the tube 10 exhausted. The temperature of the chamber is then increased until the nickelgold brazing material melts and vacuum seals the anode cap 28 to the anode eyelet 27.

Among the advantages of this invention are that the tube parts are designed and arranged to permit easy assembly thereof by mechanical means and by unskilled labor. Moreover, means are provided for positioning the tube parts relative to one another so that where very accurate spacings are required, the necessary control is provided by jigging elements. Conversely, where noncritical spacings are needed, the tube parts themselves are used to provide the desired positioning. In this manner, tubes having highly accurately spaced electrodes are provided while a minimum of jigging elements are required. This, in turn, minimizes the amount of space required within the tube to receive these jigging elements, whereby the tube may be made smaller than practical tubes of the same type made heretofore.

What is claimed is:

1. A high frequency electron discharge tube comprising an envelope including a first conductive tubular member and a header wafer closing one end of said tubular member, a plurality of conductors extending through said wafer in vacuum tight relation therewith, an electrode within said envelope secured to said conductors, and a second conductive tubular member secured to the portions of said conductors external of said envelope.

2. A high frequency electron discharge tube comprising an envelope including a conductive tubular member and a header wafer closing one end of said tubular member, a plurality of parallel conductors extending through and beyond each side of said water and in vacuum tight relation therewith, said conductors being spaced about the periphery of a circle lying in a plane perpendicular to the longitudinal axis of said tube, an electrode within said envelope secured to said conductors, and a conductive cylindrical member disposed about and secured to the portions of said conductors outside said envelope.

3. A high frequency electron discharge tube comprising a tubular envelope including an anode support enclosure closing one end of said envelope, a tubular conductive member at the other end of said envelope, a header wafer included within said tubular member and closing said other end, an annular insulating member disposed between and sealed to said anode support and said tubular member, a plurality of parallel conductors extending through said wafer in vacuum tight relation therewith, said wafer being intermediate the ends of said conductors, an anode mounted on said anode support, a cathode mounted on said conductors, and a conductive cylindrical member secured to the portions of said conductors outside said envelope and coaxial with the longitudinal axis of said tube.

4. A high frequency electron discharge device comprising an envelope and a plurality of electrodes within said envelope, said envelope including an inverted cup-shaped member closing one end of said envelope and electrically connected with one of said electrodes, said one electrode extending inwardly of said cup-shaped member, a tubular conductor member at the other end of said envelope and electrically connected with another of said electrodes, and a header Wafer secured within and closing an end of said tubular member, a plurality of parallel conductors extending through and beyond each side of said wafer in vacuum tight relation therewith, a third electrode electrically connected with said conductors, and a conductive tubular member secured to portions of said conductors outside said envelope.

5. A high frequency electron discharge tube comprising an envelope including an anode enclosure, an annular ceramic member having one end thereof sealed to said enclosure, a tubular member having one end sealed to the other end of said annular member, and a ceramic header wafer sealed within and closing the other end of said tubular member, said anode enclosure including an inverted cup-shaped end member closing an end of the tube and a side member including a first tubular portion, a second tubular portion extending within said end member, and a radial flange joining said first and said second tubular portions, said flange serving as -a seat for said end member, a plurality of tubular electrode-s within said envelope including an anode and a grid, said anode being secured within said second tubular portion, and a support member engaging said grid, said support member including a centrally disposed well for receiving an end of said grid, a radially extending flange portion, and a peripheral tubular portion secured to the inside of said tubular member and extending therealong to adjacent the end of said tubular member, said wafer engaging the end of said peripheral tubular portion and being spaced thereby from the end of said grid.

6. A high frequency electron discharge device having an envelope including a tubular member closed at one end by a disc-like header wafer having parallel faces and a side wall, the side wall of said wafer being sealed to the inside surface of said tubular member, a plurality of conductors extending through said wafer in vacuum tight relation therewith, electrodes within said envelope, one of said electrodes being secured to a plurality of said conductors, an electrode support having a centrally disposed well portion and a peripheral tubular portion, another of said electrodes being mounted within said well portion, said tubular portion being engaged with the inside surface of said tubular member and having an end engaged with the face of said wafer within said envelope for providing a preselected axial spacing of said wafer with respect to said another electrode, and a conductive cylindrical member secured to said plurality of conductors out side said envelope.

7. A high frequency electron discharge device comprising an envelope including, in sealed end to end relation, a conductive, cup-shaped top cap, a first conductive electrode support electrically connected to said top capand having a tubular portion extending within said envelope, an annular insulator, and an electrode support sub-assembly comprising a tubular outer envelope member and a tubular inner member, said inner member having a centrally disposed well portion and a peripheral portion secured to the inside surface of said outer member and extending along a portion thereof and ending adjacent to one end of said outer member, and a disc-like header Wafer having parallel faces and a side wall within said outer member, the side wall of said wafer being sealed to the inside surface of said outer member, and a face of said wafer being engaged with the end of said inner memher and being positioned thereby a preselected distance from said well portion, a first electrode secured within said tubular portion of said first electrode support, and a second electrode secured within said well portion of said inner member, said top cap providing an electrical terminal for said first electrode.

8. A high frequency electron discharge tube comprising an envelope including a conductive anode enclosure, an annular insulator having one end thereof sealed to said enclosure, a conductive tubular member having one end sealed to the other end of said annular member, and a disc-like header wafer having parallel faces and a side wall closing the other end of said tubular member, the side wall of said wafer being sealed to the wall of said tubular member, said anode enclosure including a cupshaped end member providing an end closure of said tube and a first electrode support member including a tubular portion within said end member, first and second tubular electrodes within said envelope, said first electrode being secured within said tubular portion, and a second support member engaging said second electrode, said second support member including a centrally disposed well for receiving an end of said second electrode, a radially extending flange portion, and a peripheral portion secured to the inside of said tubular member and extending along a portion thereof to adjacent the end of said tubular member and into engagement with the face of said wafer within said envelope, said end mernber providing an electrical terminal for said first electrode.

9. A high frequency electron discharge tube comprising an envelope including a conductive tubular member and a header wafer closing one end of said tubular memher, -a plurality of parallel conductors extending through and beyond each side of said wafer in vacuum tight relation therewith, some of said conductors being spaced about the periphery of a circle lying in a plane perpendicular to the longitudinal axis of said tube, an electrode Within said envelope secured to said some conductors, said some conductors extending a shorter distance outside said envelope than the remainder of said conductors, and a conductive cylindrical member disposed about and secured to said some conductors outside said envelope.

10. A high frequency electron discharge tube comprising an envelope including a conductive tubular member and a header wafer closing one end of said tubular memher, a plurality of parallel conductors extending through and beyond each side of said wafer in vacuum tight relation therewith, some of said conductors being spaced about the periphery of a circle lying in a plane perpendicular to the longitudinal axis of said tube, a cathode within said envelope secured to said some conductors, a heater within said cathode secured to others of said conductors, said some conductors extending a shorter distance outside said envelope than said others of said conductors, and a conductive cylindrical member disposed about and secured to said some conductors outside said envelope.

References Cited by the Examiner UNITED STATES PATENTS 2,029,391 2/36 Roosenstein et a1. 313-313 X 2,469,331 5/49 'Eitel et al 313-242 2,472,942 6/49 Drieschman et a1. 313-266 X 2,879,429 3/59 De Santis 313-293 2,879,430 3/59 Wadia 313-293 2,879,583 3/59 Booth et a1 29-2513 2,885,588 5/59 Wilde et al 313-293 X 2,935,782 5/60 Rangab 29-2513 JOHN W. HUCKERT, Primary Examiner.

GEORGE N. WESTBY, JAMES D. KALLAM,

Examiners. 

5. A HIGH FREQUENCY ELECTRON DISCHARGE TUBE COMPRISING AN ENVELOPE INCLUDING AN ANODE ENCLOSURE, AN ANNULAR CERAMIC MEMBER HAVING ONE END THEREOF SEALED TO SAID ENCLOSURE, A TUBULAR MEMBER HAVING ONE END SEALED TO THE OTHER END OF SAID ANNULAR MEMBER, AND A CERAMIC HEADER WAFER SEALED WITHIN AND CLOSING THE OTHER END OF SAID TUBULAR MEMBER, SAID ANODE ENCLOSURE INCLUDING AN INVERTED CUP-SHAPED END MEMBER CLOSING AN END OF THE TUBE AND A SIDE MEMBER INCLUDING A FIRST TUBULAR PORTION, A SECOND TUBULAR PORTION EXTENDING WITHIN SAID END MEMBER, AND A RADIAL FLANGE JOINING SAID FIRST AND SAID SECOND TUBULAR PORTIONS, SAID FLANGE SERVING AS A SEAT FOR SAID END MEMBER, A PLURALITYOF TUBULAR ELECTRODES WITHIN SAID ENVELOPE INCLUDING AN ANODE AND A GRID, SAID ANODE BEING SECURED WITHIN SAID SECOND TUBULAR PORTION, AND A SUPPORT MEMBER ENGAING SAID GRIG, SAID SUPORT MEMBER INCLUDING A CENTRALLY DISPOSED WELL FOR RECEIVING AN END OF SAID GRID, A RADIALLY EXTENDING FLANGE PORTION, AND A PERIPEHERAL TUBULAR PORTION SECURED TO THE INSIDE OF SAID TUBULAR MEMBER AND EXTENDING THEREALONG TO ADJACENT THE END OF SAID TUBULAR MEMBER, SAID WAFER ENGAGING HE END OF SAID PERIPHERAL TUBULAR PORTION AND BEING SPACED THEREBY FROM THE END OF SAID GRID. 